Your Opinion - Best Canon Lens Combination for Wedding Photography?

I'm not saying I completely disagree, but suggest a second look. You say you use the 17-50 mostly at the long end, I'd take a look how long you're talking because the difference from 17-24 is quite a difference... at 24mm will you be able to fit in those group shots? The other thing I'd look at is how many of your shots are at f/2.8. If you get a 24-105 you may find you're forced to crank up the ISO more, the IS can help if the subjects are still, but if you're shooting people, IS will not stop them from becoming blurred. I might lean towards adding the 70-200 f/4. Just to throw another idea out there, a prime might be useful like an 85 f/1.8 or 100 Macro. That will give you a little more telephoto, shallower Depth of field (if you want it) and the macro might be nice for ring shots and smaller detail shots (though the 85 can do a good job with those as well). I like the 85 f/1.8 it's a great lens and cheap. Also because it's lighter than the 70-200 it's easier to keep it on your back up body and have both bodies around your neck.

Also, just because FF is in your future, doesn't mean you should rule out EF-S/APS-C options entirely. For example, if someone else needed a lens to cover wide (but not super-wide) angles they might look at the 17-40 f/4 or 16-35 f/2.8, but they could get the 17-55 f/2.8 IS which has a longer range, f/2.8 aperture, sharp optics, and IS and is a lot cheaper than the 16-35. Now when they upgrade to Full frame, that 17-55 would be no good, but they could sell it and because it's a popular lens, it will hold a lot of it's value. If they had the 16-35 or 17-40, those lenses might now be too wide for what the user wants and they may have to sell them anyway to get a 24-70 or something else. Another situation might be someone who get the 24-70 now on the 7D, but by the time they upgrade to full frame Canon might upgrade the lens (add IS, make it 21-85, make it a lot sharper) and you'd be stuck with an older lens... for a lot of people "someday" ends up being a lot longer than they thought. I don't think this is much of a concern if you're looking for more telephoto lenses, as most of them are full-frame anyway... but if someone needed a super wide lens, I wouldn't say they should avoid the 10-22 just because they might want a full frame camera one day.
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~K